title: Production of anti-Helicobacter pylori metabolite by the lichen-forming fungus Nephromopsis pallescens.
abstract: The present study was conducted to evaluate the antibacterial activity of lichen-forming fungi (LFF) against Helicobacter pylori, and to optimize the culture conditions of LFF for maximum production of natural antibiotics against H. pylori. To accomplish this, a screening assay was first conducted among 19 species of LFF. The extract of Nephromopsis pallescens (KOLRI-040516) exhibited the strongest anti-ff. pylori activity. Bioautograghic TLC and HPLC analysis identified usnic acid as the main antibacterial substance produced by JV. pallescens. The growth of JV. pallescens and production of antibacterial substances produced by the fungus were then investigated under several culture conditions including the culture media, initial medium pHs, incubation temperatures, and the degree of aeration. The results indicated that culture in MY medium with an initial pH of 6.0, a temperature of 15°C and a low degree of aeration supported the largest usnic acid production of the fungus (16.4 ug usnic acid/g dry biomass). Especially, aeration was found to be an important factor that affect both growth and usnic acid production of N. pallescens.
authors.affiliation: Korean Lichen Research Institute, Sunchon National University, Sunchon, 540-742, Republic of Korea.
authors.forename: Heng
authors.initials: H
authors.lastname: Luo
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Yamamoto
authors.forename: Hae-Sook
authors.initials: HS
authors.lastname: Jeon
authors.forename: Yan Peng
authors.initials: YP
authors.lastname: Liu
authors.forename: Jae Sung
authors.initials: JS
authors.lastname: Jung
authors.forename: Young Jin
authors.initials: YJ
authors.lastname: Koh
authors.forename: Jae-Seoun
authors.initials: JS
authors.lastname: Hur
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D001203:Ascomycota / Q000254:growth & development* / Q000378:metabolism*; D001572:Benzofurans / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D003470:Culture Media / Q000737:chemistry; D016480:Helicobacter pylori / Q000187:drug effects* / Q000254:growth & development*; D006863:Hydrogen-Ion Concentration; D008826:Microbial Sensitivity Tests; D013696:Temperature
chemical_list: D000900:Anti-Bacterial Agents; D001572:Benzofurans; D003470:Culture Media; C073339:usnic acid